Effect of different lead precursors on perovskite solar cell performance and stability

Abstract

We present the use of halide (PbCl₂) and non-halide lead precursors (Pb(OAc)₂ (OAc = CH₃CH₂COO⁻), Pb(NO₃)₂, Pb(acac)₂ (acac = (CH₃COCHCOCH₃)⁻) and PbCO₃) for the preparation of perovskite solar cells. We have confirmed by X-ray diffraction the growth of CH₃NH₃PbI₃ in all the analyzed cases, except for PbCO₃, independently of the lead precursor used for the synthesis of the perovskite. In addition, different cell configurations, thin films and mesoporous scaffolds, TiO₂ or Al₂O₃, have also been prepared. We have observed that the lead precursor has a strong influence on the structural properties of perovskite (grain size), as well as on the solar cell performance. Photovoltaic conversion efficiencies comparable to those achieved when using the commonly employed PbCl₂ have been obtained with Pb(OAc)₂ as a lead source. Stability studies of the perovskite films and devices have also been carried out, which demonstrate that the lead precursor also plays a role. The stability is not only strongly affected by atmosphere and illumination conditions, but also by the lead precursor employed for the perovskite synthesis. These results highlight that other lead sources, different to the commonly used PbCl₂ and PbI₂, are also suitable for the development of PSCs, opening a new way for device performance optimization.